Patient interfaces

ABSTRACT

The present invention relates to a device for delivering a supply of gases to a patient. The device includes a patient interface and connecting member. The connecting member is preferably a L-shaped swivelled connector that is capable of being fixed into one of two positions, a first position where the connector is freely rotatable within the patient interface, and a second position where an interference between the interface and connector prevents the free rotation of the connector within the patient interface. The present invention further relates to a connector that has outlet means, which includes at least one outlet vent and a funnel, which in use directs and passes a substantial portion gases expired from the patient through the outlet vent or vents.

BACKGROUND OF THE INVENTION

[0001] Field of the Invention

[0002] This invention relates to patient interfaces, particularly thoughnot solely for use in providing Continuous Positive Airway Pressure(CPAP) therapy or positive pressure ventilation to patients sufferingfrom obstructive sleep apnoea (OSA).

SUMMARY OF THE PRIOR ART

[0003] In the art of respiration devices, there are well known a varietyof respiratory masks which cover the nose and/or mouth of a human userin order to provide a continuous seal around the nasal and/or oral areasof the face such that gas may be provided at positive pressure withinthe mask for consumption by the user. The uses for such masks range fromhigh altitude breathing (ie. aviation applications) to mining and firefighting applications, to various medical diagnostic and therapeuticapplications.

[0004] One requisite of such respiratory masks has been that theyprovide an effective seal against the patient's face to prevent leakageof the gas being supplied. Commonly, in prior mask configurations, agood mask-to-face seal has been attained in many instances only withconsiderable discomfort for the user. This problem is most crucial inthose applications, especially medical applications, which require theuser to wear such a mask continuously for hours or perhaps even days. Insuch situations, the user will not tolerate the mask for long durationsand optimum therapeutic or diagnostic objectives thus will not beachieved, or will be achieved with great difficulty and considerableuser discomfort.

[0005] Where such masks are used in respiratory therapy, in particulartreatment of obstructive sleep apnoea (OSA) using continuous positiveairway pressure (CPAP) therapy, there is generally provided in the art avent for washout of the bias flow or expired gases to the atmosphere.Such a vent may be provided for example, as part of the mask, or in thecase of some respirators where a further conduit carries the expiratorygases, at the respirator. A further requisite of such masks is thewashout of gas from the mask to ensure that carbon dioxide build up doesnot occur over the range of flow rates. In the typical flow rates inCPAP treatment, usually between 4 cm H₂O and 20 cm H₂O, prior artattempts at such vents have resulted in excessive noise causingirritation to the user and any bed partners.

[0006] Various approaches have been developed in the prior art toattempt to reduce the noise when CPAP therapy is provided. For example,in PCT Patent Application No. WO98/34665 it has been proposed that thevent include a resilient plug with rounded edge apertures to reproducenoise. However, this is not entirely effective in eliminating the extranoise created by a vent at the mask.

[0007] In common with all attempts to improve the fit, sealing and usercomfort is the need to avoid a concentrated flow of air at any portionof the respiratory tracts. In particular with oral masks or mouthpiecesit is a disadvantage of prior art devices that the oral cavity maybecome overly dehydrated by use of the device, causing irritation andpossible later complications.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to attempt to provide apatient interface which goes some way to overcoming the abovementioneddisadvantages in the prior art or which will at least provide theindustry with a useful choice.

[0009] Accordingly in a first aspect the present invention consists in adevice for delivering a supply of gases to a patient comprising orincluding:

[0010] a patient interface fittable to said patients' nose or mouth,which in use is in fluid communication with said supply of gases,

[0011] connecting member having two ends and interface means, one end ofsaid two ends being locatable within said patient interface and theother end of said two ends is connectable to said supply of gases, saidmember capable of being fixed into one of two positions, a firstposition where said member is freely rotatable within said patientinterface, and a second position where said interference means preventsthe free rotation of said member within said patient interface.

[0012] In a second aspect the present invention consists in a continuouspositive airways pressure system for delivering gases to a patientcomprising or including a pressurised source of gases, transport means,in fluid communication with said pressurised source, adapted to conveysaid gases, and a nasal mask in fluid communication with said transportmeans, in use, delivering said gases to said user, said nasal maskcomprising or including:

[0013] a body portion having an inlet, connected to said transportationmeans by a connecting member,

[0014] sealing means engaged with said body portion, and adapted to sealagainst the facial contours of said patient, and

[0015] securement means attached to or around the head of said user,

[0016] wherein said connecting member has two ends and interferencemeans, one end being locatable within said patient interface and theother end of said two ends connectable to said transportation means,said connecting member capable of being fixed into one of two positions,a first position where said member is rotatable within said patientinterface, and a second position where said interference means preventsthe free rotation of said member within said patient interface.

[0017] In a third aspect the present invention consists in a device fordelivering a supply of gases to a patient comprising:

[0018] a patient interface, which in use is in fluid communication withsaid supply of gases,

[0019] connecting member that connects said patient interface with saidsupply of gases,

[0020] outlet means associated with said connecting member, said outletmeans including at least one outlet vent and a funnel, which in usedirects and passes a substantial portion gases expired from said patientthrough said at least one outlet vent.

[0021] To those skilled in the art to which the invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the scope of the invention as defined in the appended claims. Thedisclosures and the descriptions herein are purely illustrative and arenot intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One preferred form of the present invention will now be describedwith reference to the accompanying drawings in which;

[0023]FIG. 1 is a block diagram of a humidified positive pressureventilation system as might be used in conjunction with the presentinvention,

[0024]FIG. 2 is an illustration of the nasal mask in use according tothe preferred embodiment of the present invention,

[0025]FIG. 3 is a side elevation view of an example of a connector usedwith a breathing circuit,

[0026]FIG. 4 is a perspective view from above of a mouthpiece that maybe used with the elbow connector of the present invention,

[0027]FIG. 5 is a perspective view from one side and from an inwarddirection of the mouthpiece of FIG. 4,

[0028]FIG. 6 is a cross-section of the mouthpiece of FIG. 4,

[0029]FIG. 7 is a cross-sectional view of the mouthpiece of FIG. 4 and auser with the mouthpiece in place to demonstrate the location andpositioning thereof in relation to the main features of the patient'sanatomy,

[0030]FIG. 8 is a perspective view of the mouthpiece with an outer flapin place,

[0031]FIG. 9 is a perspective view of the outer flap bent back,

[0032]FIG. 10 is a cutaway view of the mouthpiece with the outer flap inuse,

[0033]FIG. 11 is a perspective view of the outer flap including theventilation apertures and moisture barrier,

[0034]FIG. 12 is a front view of a nasal mask, including a swivelledelbow connection of the present invention,

[0035]FIG. 13 is a side view of the swivelled elbow connection asattached to the mask body of the present invention in a first position,

[0036]FIG. 14 is an exploded side view of the locking mechanism part ofthe swivelled elbow connection in the first position,

[0037]FIG. 15 is a side view of the swivelled elbow connection asattached to the mask body of the present invention, in a secondposition,

[0038]FIG. 16 is an exploded side view of the locking mechanism part ofthe swivelled elbow connection in the second position,

[0039]FIG. 17 shows a nasal mask body and elbow connector with diffuser,

[0040]FIG. 18 shows a cutaway side view of the bias flow director of thepresent invention, and

[0041]FIG. 19 shows a cutaway perspective view of the bias flow directorof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The present invention provides improvements in the delivery ofpositive pressure ventilation therapy. In particular a patient interfaceis described which is quieter for the user to wear and reduces the sideleakage as compared with the prior art. The patient interface of thepresent invention includes improvements to the swivel elbow connector,bias flow directional funnel and/or elbow diffuser. It will beappreciated that the patient interface as described in the preferredembodiment of the present invention can be used in respiratory caregenerally or with a ventilator but will now be described below withreference to use in a humidified positive pressure ventilation system.It will also be appreciated that the present invention can be applied toany form of patient interface including, but not limited to, nasalmasks, oral masks and mouthpieces.

[0043] With reference to FIG. 1 a humidified positive pressureventilation system is shown in which a patient 1 is receiving humidifiedand pressurised gases through a patient interface 2 connected to ahumidified gases transportation pathway or inspiratory conduit 3. Itshould be understood that delivery systems could also be YPAP (VariablePositive Airway Pressure) and BiPAP (Bi-level Positive Airway Pressure)or numerous other forms of respiratory therapy. Inspiratoxy conduit 3 isconnected to the outlet 4 of a humidification chamber 5, which containsa volume of water 6. Inspiratory conduit 3 may contain heating means orheater wires (not shown), which heat the walls of the conduit to reducecondensation of humidified gases within the conduit. Humidificationchamber 6 is preferably formed from a plastics material and may have ahighly heat conductive base (for example an aluminium base) which is indirect contact with a heater plate 7 of humidifier 8. Humidifier 8 isprovided with control means or electronic controller 9 which maycomprise a microprocessor based controller executing computer softwarecommands stored in associated memory.

[0044] Controller 9 receives input from sources such as user input meansor dial 10 through which a user of the device may, for example, set apredetermined required value (reset value) of humidity or temperature ofthe gases supplied to patient 1. The controller may also receive inputfrom other sources, for example temperature and/or flow velocity sensors11 and 12 through connector 13 and heater plate temperature sensor 14.In response to the user set humidity or temperature value input via dial10 and the other inputs, controller 9 determines when (or to what level)to energise heater plate 7 to heat the water 6 within humidificationchamber 5. As the volume of water 6 within humidification chamber 5 isheated, water vapour begins to fill the volume of the chamber above thewater's surface and is passed out of the humidification chamber 5 outlet4 with the flow of gases (for example air) provided from a gases supplymeans or blower 15 which enters the chamber through inlet 16. Exhaledgases from the patient's mouth are passed directly to ambientsurroundings.

[0045] Blower 15 is provided with variable pressure regulating means orvariable speed fan 21, which draws air or other gases through blowerinlet 17. The speed of variable speed fan 21 is controlled by electroniccontroller 18 (or alternatively the function of controller 18 could becarried out by controller 9) in response to inputs from controller 9 anda user set predetermined required value (preset value) of pressure orfan speed via dial 19.

[0046] Nasal Mask

[0047] A nasal mask that nay be used with the improvements to the swivelelbow connector, bias flow directional funnel and/or elbow diffuser ofthe present invention is shown in FIG. 2. The mask includes a hollowbody 102 with an inlet 103 connected to the inspiratory conduit 3. Themask 2 is positioned around the nose of the user 1 with the headgear 108secured around the back of the head of the patient 1. The restrainingforce from the headgear 108 on the hollow body 102 and the forehead rest106 ensures enough compressive force on the mask cushion 104, to providean effective seal against the patient's face.

[0048] The hollow body 102 is constructed of a relatively inflexiblematerial for example, polycarbonate plastic. Such a material wouldprovide the requisite rigidity as well as being transparent and arelatively good insulator.

[0049] The improved swivel elbow connector, bias flow directional funneland/or elbow diffuser of the present invention may also be used with amouthpiece as described below, or with a full facial mask.

[0050] Mouthpiece

[0051] Referring to FIGS. 3 to 10 a mouthpiece that may utilise theimprovements to the swivel elbow connector, bias flow directional funneland/or elbow diffuser. In this embodiment, the mouthpiece 50 includes avestibular shield 49 being a generally flat and generallyrectangularly-shaped member in front elevation having a curved profilethat reflects the curvature of a patient's jaw and in turn the curvatureof the labial vestibule region A gases passageway extends through thevestibular shield from an inlet 51 to an outlet 52 in much the same wayas with the earlier embodiments. The inlet 51 is provided by a flattenedoval-shaped connector 53. The outlet 52 has an even more laterallyextended flattened oval shape 54. Most prominently, the mouthpiece SOincludes a tongue depressor 55 extending from the inner face of thevestibular shield 49. The operation of the tongue depressor will bedescribed further on with reference to FIG. 5. The tongue depressorincludes a vertical stiffening flange 56 centrally located on its uppersurface and extending from the gases outlet 52. In use gases flow easilyaround the stiffening flange 56 effectively bifurcating the gases outlet52. The tongue depressor 55 further includes a pair of verticallyextending spacers 57, which in use may abut against the roof of thepatient's mouth and ensure that the tongue cannot completely block theair passageway. In the mouthpiece 50 the sealing effect of thevestibular shield 49 against the lips of the user is enhanced byproviding teeth abutments of significantly increased thickness than theraised area 20 of the earlier embodiments. In particular, an upper teethabutment 58 and a lower teeth abutment 59 are provided, with the lowerteeth abutment 59 protruding further from the inner face of thevestibular shield 49 than the upper teeth abutment 58. This differenceserves to match the typical over-bite of most users. The abutments 58and 59 are not required to be wider than the gases outlet 52.

[0052] A notch 60 is provided centrally in the upper edge of thevestibular shield 49 to accommodate the upper frenal attachment. Aslight bead 61 is provided around the edge of the vestibular shield 49for user comfort, with the vestibular shield 49 otherwise being verythin for additional suppleness.

[0053] Referring particularly to FIG. 6, the mouthpiece 50 is preferablyformed by over-moulding a soft and supple material part 70 over astiffer material part 67. These can generally be termed the shield partand the passageway-forming insert. The passageway-forming insertpreferably includes a pair of upper and lower vertical flanges 63 and 64to fully engage within the supple material. The passageway-forminginsert 67 includes the vertically extending stiffening flange 56 of thetongue depressor 55, together with a curved planar portion 71 formingthe backbone of the tongue depressor 55. The vertically extendingspacers 57 are of the soft and supple material and are part of theover-moulding 70, as are the upper and lower teeth abutments 58 and 59.

[0054] Referring now to FIG. 7, use of the mouthpiece according to FIGS.4 to 6 is depicted. With the present mouthpiece 50, the upper and lowerlips 85, 86 are further distended by the abutment action of theabutments 75, 76 against the upper and lower teeth 87, 88 respectively,thus forming a seal of greater pressure between the lips 85, 86 and theupper and lower portions respectively of the vestibular shield 49. Alower face 77 of the tongue depressor 55 impinges if necessary on theupper surface 72 of the tongue 85 and retains the tongue in the lowerportion of the mouth. This ensures a clear gases outlet 52 from thegases passageway through the vestibular shield. The vertically extendingspacers 57, if forced by pressure from the tongue, will engage againstthe roof of the patient's mouth and maintain a clear air passageway.This stops the sleeping patient unconsciously blocking the oralpassageway and reverting to nasal breathing.

[0055] Referring now to FIG. 8 of the present invention is illustratedincluding an extra-oral sealing flap 110. The flap 110 in its naturalbias is tapered, the wide-open end of which is shaped to conform to thefacial contours around the outside of the mouth of a user. The narrowend joins to a cylindrical section, which is designed to slide over theinlet port 114 of the mouthpiece 112. While this is one method ofattachment the flap 100 might also be constructed as an integral part ofthe mouthpiece 112. The flap 110 needs to be constructed of flexiblematerial. Therefore, materials such as silicone rubber can be employedto fashion the flap.

[0056] The outer flap 110 is seen in FIG. 9, in a bent back position. Itwill be appreciated that when the mouthpiece 112 is being inserted intothe mouth of a users the outer flap 110 is intended to be in this bentback position to aid insertion. Prior to insertion, the outer flap isbent back by simply pressing on its outer periphery 116, until it snapsinto the bent back position, in which it will stay unaided.

[0057] In FIG. 10 we see the outer flap 110 in use with the mouthpiece112 in the mouth 117 of a user 120. Once correctly positioned in themouth 116, the outer flap 110 may be adjusted into its operationalposition by pressing on its outer periphery 116 until it snaps back topress against the outside of the mouth 118. Due to the relative positionof the vestibular shield 122 and the outer flap 110, the outer flap 110is unable to fully reach its natural bias and thereby inflicts acompressive force on the outside of the mouth 118.

[0058] It will be appreciated that as well as providing a substantiallyairtight seal the addition of the outer flap provides enough compressiveforce on the mouth to keep the mouthpiece and conduit in place withoutthe need for straps. This allows the administering of positive airwaypressure ventilation therapy to be considerably less obtrusive thantraditional methods.

[0059] In a further additional improvement shown in FIG. 11, the outerflap 300 is shown in perspective. Included are ventilation apertures302, 303 either side of the gases port 304, which are surrounded by aridge 306 acting as a moisture barrier. The apertures 302, 303 areprovided such that any excess moisture leaking from the mouth willmigrate to the apertures where they may evaporate. Small vents in theconduit may be used to direct small amounts of pressurised gas at theapertures to aid evaporation. The ridge 306 is included to ensure thatno moisture migrates further into the sealing region 308, as this wouldbe detrimental to the sealing properties of the flap.

[0060] Interface Connection

[0061] Attention is now directed to FIG. 3. It has been found that anadditional factor in the effectiveness of any patient interface 2, isthe manner in which the interface is connected to the breathing circuit.The weight of the breathing circuit, and any attempted movement of oneother of the breathing circuit and the interface 2 relative to theother, is one of the largest influences tending to dislodge theinterface 2. It must be noted that the interface 2 must remain inposition and maintain a seal during all sleep, when the user has nomuscle tone.

[0062] The connection is usually provided between a breathing circuitand an interface 2, which decouples the interface 2 from the breathingcircuit. This type of configuration is shown in FIG. 3, where theinterface is a mouthpiece, although a nasal mask may be used in place ofthe mouthpiece. The connection 40 is effective in reducing the forcesplaced on the interface 2 by the breathing circuit 41 when the usermoves around during sleep.

[0063] To connect between the gases outlet 42, which is vertical whenthe user is lying on his or her back, and the breathing circuit 41,which is generally horizontal, a L-shaped elbow connector 45 isincorporated in the connection 40. The elbow connector 45 may beincorporated in the interface 2. The elbow connector 45 is formed at aright angle and provides a positive pressure on the interface 2. Theelbow connector 45 may include a swivel joint and may be disconnectedfrom gaseous outlet 42. The connection 40 further includes a connectingtube 46 provided between the elbow 45 and the breathing circuit 41. Theconnecting tube 46 is preferably connected to the breathing circuit 41by a swivel joint 48 for reasons described herein. The breathing circuit41, while flexible, will necessarily be stiff enough to maintain itsinter over comparatively long tuns, while the flexible connecting tube46, being only a short length, for example 10 centimetres, merely has tospan between the patient's mouth and chest, and can thereby be made in amanner that would not be suitable for long runs. Furthermore, as aresult of the short length of the connecting tube 46, the connectingtube 46 does not need to incorporate significant insulation or heatingcapability. The connecting tube 46 may be formed from a thin plasticmembrane supported over helical or double helical or corrugatedsupporting ribs. In such a case, the support makes the connection tube46 laterally flexible and resistant to torsion. The elbow swivelconnector 45 allows for movement of the connection tube 46 relative tothe interface 2. The swivel connector 48 allows for movement of theconnection tube 46 relative to the breathing circuit 41. It is to beunderstood that one or both of the swivel joints 45, 48 could beeliminated, but the preferred embodiment includes elbow swivel connector48.

[0064] Fixable Swivel Joint

[0065] The nasal mask or mouthpiece as described above can be providedwith an improved L-shaped elbow connector similar to that describedabove. Referring to FIGS. 12 to 16 a L-shaped elbow 401 is fixed to themask base 402 on the nasal mask although not shown in the Figures toinlet 51 of the mouthpiece 50. Hereinafter when reference is made to“mask body” or “mask base 402” it is intended to refer to either themask body or inlet 51 of the mouthpiece. A portion 403 of the elbowconnector can be rotated about a point X in the directions of arrows Aand B. The elbow connector 401 is connectable at its end 404 to thebreathing circuit or conduit 3 as described with reference to FIGS. 1and 2. The connector 401 is designed to be fixed into one of twopositions and is able to be fully removed from the mask base 402. If theconnector 401 is assembled in a first position, it is able to freelyswivel, as indicated by the arrows labelled A and B on FIG. 12. If theelbow is pushed into a second position, an area of interference preventsthe connector from freely swivelling.

[0066] Attention is now drawn to FIGS. 13 and 14 where he mask body 501and elbow connector 502 are shown in a first position where theconnector 502 is able to freely rotate 360 degrees about a vertical axisout of the mask body. The connector 502 is connected to an aperture inthe centre of the mask body, so that in use, gases flow from thebreathing circuit through the elbow connector and aperture in the maskbody and into the patient's lungs. The elbow connector 502 is heldwithin the aperture in the mask body 501 by way of tubular connector 503located on the arm of the elbow connector 502. The tubular connector 503comprises various ridges and protrusions, moulded in the externalsurface of the elbow connector's arm, that meet with complimentaryridges and protrusions moulded in the interior surface of the aperturein the mask body (or the inlet 51 itself).

[0067] In particular, referring to FIG. 14, when the connector 502 is inthe position as shown in FIG. 13, the ridge 601 and protrusion 602 inthe connector 502 act with the small ridge 603 and protrusion 604 in theinterior surface of the mask body, to lock the elbow connector 502 intoa position that enables the elbow to swivel freely within the mask body.To remove the elbow 502 from the mask body 501 a force in the directionof arrow C (see FIG. 13) must be placed on the elbow so that theprotrusion 602 on the elbow is forced past the protrusion 604 on themask body, thereby releasing the connector 502 from the mask body.

[0068] The elbow connector may be pushed downwards to into the mask bodyto a position as shown in FIGS. 15 and 16. Here, the protrusion 602 ofthe elbow has been pushed past the lower protrusion 802 on the mask body501 and sits within a complimentary ridge 801 in the mask. Theprotrusion 604 on the mask abuts the ridge 601 on the elbow connectorand the exterior side surface 804 of the elbow connector above the ridge601 abuts the interior surface 805 of the mask aperture. The area ofinterference 803 between these surfaces prevents the elbow from freelyswivelling within the mask.

[0069] The improvements, as described above, to the elbow connector ofthe present invention provides an attachment that can either freelyrotate, or be locked in a particular position according to the patient'sdesires. The improvement to the prior art swivel connectors is that theshort flexible tubing (46 as described with reference to FIG. 3) is nolonger required.

[0070] Flow Diffuser and Bias Flow Directional Funnel

[0071] In an alternative form of the present invention, and in order toreduce the noise caused by expiratory gases being expelled from the maskor mouthpiece, either may be provided with an elbow connector having adiffuser. In prior art systems the flow diffuser is usually providedwithin the elbow connector at the point of connection to the mask bodyor inlet to the mouthpiece, in the present invention it is envisaged toprovide a diffuser on the elbow connector. The following descriptionrefers to nasal mask when describing the diffuser. The diffuser may alsobe provided with an elbow connector used with a mouthpiece as previouslydescribed.

[0072]FIG. 17 shows a nasal mask 901 and elbow connector 902 as that hasa diffuser located along the length of the connector 902 previously. Theelbow connector 902 includes a diffuser 903 on its exterior surface, thediffuser is a duct that provides for the broadening of the airflow andreduction in the airflow speed. In the preferred form the duct hasoutlet vent holes 904, 905 and the duct is made out of flexible rubbermaterial. Note must be made that any number of vent holes may beprovided in the duct, the preferred form shown in FIG. 17, merely showstwo vents. The duct is preferably provided with a bias flow directionalfunnel, which will be described below.

[0073] Referring to FIGS. 18 and 19, during positive pressureventilation treatment a portion of the inlet air flow breathed by thepatient is exhausted directly through the bias holes 1001, 1002. Theonly venting required is to clear the expired CO₂ gas from within theelbow connector 1003. Therefore a funnel 1004 is provided within theelbow 1003 that directs the exhaled CO, gases to the bias holes 1001,1002 but does not direct the inlet airflow from the ventilation machineout the bias holes.

[0074] The purpose of the funnel is to vent exhaled air from thebreathing system to remove CO₂ gases. With the prior art breathingsystems it has been found that there is continuous leaking of gasesthrough the vent holes during inspiration and expiration by the patient.Therefore, a loss of pressure occurs due to escaping air. Thus, oninspiration the patient receives less pressure and thus less breathingtherapy, and therefore this requires that vent holes are provided thatare as small as possible to lessen this effect.

[0075] During expiration by the patient it is preferred that most of theexhaled gases are vented through the vent holes, in order to preventpressure spikes and to ensure CO₂ gases are expelled from the breathingtubing. The funnel therefore provides for shielding of the vent holesduring inspiration, but enhances the venting of CO₂ gases by providingdirectional flows during expiration, this also allows for vent holes tobe increased in size, providing larger exhaust areas.

[0076] Inlet airflow E flows from the ventilating system through theelbow connector in the direction of arrows F, G and H and into thepatient's lungs. The air that is exhaled, as indicated by arrow I, flowsthrough the funnel 1004 that has been moulded within the interior of theelbow 1003. The funnel 1004 is tubular in shape and provides for thefunnelling of the exhausted CO₂ gases through the outlet bias holes1001, 1002.

[0077] Providing such a diffuser on the elbow connector effectivelyminimises the noise generated by the outward flow of expiratory gasesfrom the mask. The diffuser of the present invention requires little orno maintenance and improves user comfort.

[0078] The providing of a directional funnel within the elbow connectorfurther minimises noise and reduces pressure spikes during exhalation.

What is claimed is:
 1. A device for delivering a supply of gases to apatient comprising or including: a patient interface fittable to saidpatients nose or mouth, which in use is in fluid communication with saidsupply of gases, connecting member having two ends and interface means,one end of said two ends being locatable within said patient interfaceand the other end of said two ends is connectable to said supply ofgases, said member capable of being fixed into one of two positions, afirst position where said member is freely rotatable within said patientinterface, and a second position where said interference means preventsthe free rotation of said member within said patient interface.
 2. Adevice for delivering a supply of gases to a patient according to claim1 wherein said other end is connected to transport means that isconnected to said supply of gases.
 3. A device for delivering a supplyof gases to a patient according to claim 1 wherein said connectingmember is a L-shaped connector.
 4. A device for delivering a supply ofgases to a patient according to claim 1 wherein said interface means isthe meeting of surfaces on each of the mask and connecting member.
 5. Adevice for delivering a supply of gases to a patient according to claim1 wherein said patient interface is a nasal mask.
 6. A device fordelivering a supply of gases to a patient according to claim 1 whereinsaid patient interface is a mouthpiece.
 7. A device for delivering asupply of gases to a patient according to claim 5 wherein said nasalmask comprises or includes: a body portion, having an inlet receivingsaid supply of gases through said transport means, and sealing meansattached to or integrated with said body portion, said sealing meansadapted to seal against the facial contours of said patient.
 8. A devicefor delivering a supply of gases to a patient according to claim 7wherein said connecting member includes outlet means, said outlet meansincluding, at least one outlet vent and a funnel which in use directsand passes a substantial portion of gases expired from said patientthrough said at least one outlet vent.
 9. A continuous positive airwayspressure system for delivering gases to a patient comprising orincluding a pressurised source of gases, transport means, in fluidcommunication with said pressurised source, adapted to convey saidgases, and a nasal mask in fluid communication with said transportmeans, in use, delivering said gases to said user, said nasal maskcomprising or including: a body portion having an inlet, connected tosaid transportation means by a connecting member, sealing means engagedwith said body portion, and adapted to seal against the facial contoursof said patient, and securement means attached to or around the head ofsaid user, wherein said connecting member has two ends and interferencemeans, one end being locatable within said patient interface and theother end of said two ends connectable to said transportation means,said connecting member capable of being fixed into one of two positions,a first position where said member is rotatable within said patientinterface, and a second position where said interference means preventsthe free rotation of said member within said patient interface.
 10. Adevice for delivering a supply of gases to a patient according to claim9 wherein said other end is connected to a conduit that is connected tosaid supply of gases.
 11. A device for delivering a supply of gases to apatient according to claim 8 wherein said connecting means is a L-shapedconnector.
 12. A device for delivering a supply of gases to a patientaccording to claim 9 wherein said interface means is the meeting ofsurfaces on each of said patient interface and said connecting means.13. A device for delivering a supply of gases to a user according toclaim 9 wherein said patient interface is a nasal mask.
 14. A device fordelivering a supply of gases to a user according to claim 9 wherein saidpatient interface is a mouthpiece.
 15. A device for delivering a supplyof gases to a user according to claim 13 wherein said nasal maskcomprises or includes: a body portion having an inlet receiving saidsupply of gases through said conduit and said connecting member, andsealing means attached to or integrated with said body portion saidsealing means adapted to seal against the facial contours of saidpatient.
 16. A continuous positive airways pressure system fordelivering gases to a patient according to claim 15 wherein saidconnecting member includes outlet means, said outlet means including, atleast one outlet vent and a funnel, which in use directs and passes asubstantial portion of gases expired from said patient through said atleast one outlet vent.
 17. A device for delivering a supply of gases toa patient comprising: a patient interface, which in use is in fluidcommunication with said supply of gases, connecting member that connectssaid patient interface with said supply of gases, outlet meansassociated with said connecting member, said outlet means including atleast one outlet vent and a funnel, which in use directs and passes asubstantial portion gases expired from said patient through said atleast one outlet vent.
 18. A device for delivering a supply of gases toa patient according to claim 17 wherein said funnel in use shields saidat least one outlet vent from gases supplied to said patient by saidsupply of gases.
 19. A device for delivering a supply of gases to apatient according to claim 17 wherein said outlet means includes aflexible portion and said at least one outlet vent is formed in saidflexible portion.
 20. A device for delivering a supply of gases to auser according to claim 17 wherein said patient interface is amouthpiece.
 21. A device for delivering a supply of gases to a useraccording to claim 17 wherein said patient interface is a nasal mask.22. A device for delivering a supply of gases to a user according toclaim 17 wherein said connecting member has two ends and interfacemeans, one end of said two ends being locatable within said patientinterface and the other end of said two ends connectable to said supplyof gases said connecting member able to be fixed into one of twopositions, a first position where said member is freely rotatable withinsaid patient interface, and a second position where said interferencemeans prevents the free rotation of said member within said patientinterface.
 23. A device for delivering a supply of gases to a patientaccording to claim 22 wherein said other end is connected to transportmeans that is connected to said supply of gases.
 24. A device fordelivering a supply of gases to a patient according to claim 22 whereinsaid connecting member is a L-shaped connector.
 25. A device fordelivering a supply of gases to a patient according to claim 22 whereinsaid interference means is the meeting of surfaces on each of the maskand connecting member.
 26. A device for delivering a supply of gases toa user according to claim 22 wherein said outlet means is located onsaid connecting member.